DiversityNursing Blog

A new study that offers insights into early language development suggests babies prefer listening to other babies rather than adults as they get ready to produce their own speech sounds.

The study, led by McGill University in Canada and published in the journal Developmental Science, observed the reactions of infants aged from 4-6 months who were not yet attempting speech, as they listened to baby-like and adult-like sounds produced by a voice synthesizer.

They found when the vowel sounds the babies listened to sounded more baby-like (for instance, higher pitch), the infants paid attention longer than when the sounds had more adult-like vocal properties.

Previous studies have shown that children at this age are more attracted to vocal sounds with a higher voice pitch, the authors note in their paper.

The team says the finding is important because being attracted to infant speech sounds may be a key step in babies being able to find their own voice - it may help to kick-start the process of learning how to talk.

They say the discovery increases our understanding of the complex link between speech perception and speech production in young infants.

It may also lead to new ways to help hearing-impaired children who may be struggling to develop language skills, they note.

Baby-like sounds held infants' attention nearly 42% longer

For the study, the team used a voice synthesizer to create a set of vowel sounds that mimicked either the voice of a baby or the voice of a woman.

They then ran a series of experiments where they played the vowel sounds one at a time to the babies as they sat on their mother's lap and listened. They measured the length of time each vowel sound held the infants' attention.

The results showed that, on average, baby-like sounds held the infants' attention nearly 42% longer than the adult-like sounds.

The researchers note that this finding is unlikely to be a result of the babies having a particular preference for a familiar sound because they were not yet producing those sounds themselves - they were not yet part of their everyday experience.

Some of the infants showed their interest in other ways. For example, when they listened to the adult sounds, their faces remained fairly passive and neutral. In contrast, when they heard the baby-like sounds, they became more animated, moved their mouths and smiled.

The following video shows how one of the infants - baby Camille, who is not yet babbling herself - reacts to the various sounds. Every time she looks away, the sound is replaced by another. Her reactions show which sounds she seems to like the most.

Babies need to 'find their own voice'

The researchers say maybe the babies recognized that the baby-like sounds were more like sounds they could make themselves - despite not having heard them before.

The findings may also explain the instinct some people have when they automatically speak to infants in baby-like, high-pitched tones, says senior author Linda Polka, a professor in McGill's School of Communication Disorders, who adds:

"As adults, we use language to communicate. But when a young infant starts to make speech sounds, it often has more to do with exploring than with communicating."

Prof. Polka says babies often try speaking when they are on their own, without eye contact or interaction with others. She explains:

"That's because to learn how to speak babies need to spend lots of time moving their mouths and vocal cords to understand the kind of sounds they can make themselves. They need, quite literally, to 'find their own voice.'"

Funds for the study came from the Natural Sciences Engineering and Research Council.

Meanwhile, parents and schools looking for ways to encourage children to eat more healthily may be interested in a study carried out among kindergarten through sixth-grade students at an inner-city school in Cincinnati, OH. There, researchers discovered that children found healthy food more appealing when linked to smiley faces and other small incentives. The low-cost intervention led to a 62% rise in vegetable purchases and a 20% rise in fruit purchases.

Researchers testing the origins of human breast milk samples available for purchase online found that around 10% of the samples they examined contained significant amounts of added cow's milk.

The pressure on parents to feed newborn infants with breast milk may be leading many to purchase human breast milk online. However, the milk they receive from online vendors may not match up to what is being offered.

"They purchase the milk online based on a posted description of the type and quantity of the milk or the health habits of the seller," writes study author Dr. Sarah Keim. "But when they think they're getting nutritious, high-quality breast milk, some of them are actually receiving human milk mixed with cow's milk."

Human breast milk is widely recognized as providing many health benefits to young infants. According to the American Academy of Pediatrics (AAP), breastfeeding can protect against diseases and conditions such as diarrhea, diabetes and childhood obesity.

However, many new mothers find themselves unable to breastfeed. In 2012, a survey published in Pediatrics found that two-thirds of mothers nursing newborns are unable to manage breastfeeding for as long as they intended.

"Some women are unable to produce enough milk for their infant or perceive they cannot meet their infant's needs, yet they may be reluctant to feed formula," write the researchers of the new study. For these mothers, the Internet represents an alternative way of providing human milk for their children.

'You do not truly know what you are receiving'

For the study, published in Pediatrics, Dr. Keim and her colleagues purchased 102 samples of what was advertised as human milk from sellers on the Internet. These milk samples were subjected to DNA testing in order to verify their human origins and to assess whether any cow's milk was also present.

While all of the purchased Internet samples contained human DNA, 11 also contained bovine DNA. Of these, 10 contained bovine DNA concentrations significant enough to suggest that cow's milk had been added to human milk, being so high that accidental contamination was unlikely.

The inclusion of cow's milk in human breast milk can be problematic for babies. It can potentially be harmful due to cow's milk allergies, health conditions or formula sensitivities. The inclusion of cow's milk could also reduce a baby's access to the essential nutrients and fats that are in formulas and human breast milk but not cow milk.

"The truth of the matter is that you do not truly know what you are receiving when you buy milk from a stranger over the Internet," explains Dr. Keim.

"Selling breast milk gives people an incentive to add cow's milk or formula to the milk in order to sell more. When money is involved in an unregulated process like this, you cannot know for sure that the milk is safe to give to your baby."

Although the sample used in the study is acknowledged as small by the authors, they state the sample is representative of Internet sellers and has given the researchers findings that may at least generalize to milk being sold via the Internet.

"Our findings confirm the previously theoretical risk that human milk being sold via the Internet may not be 100% human milk," the authors conclude. "Because buyers have little means to verify the composition of the milk they receive, all should be aware of the possibility that it may be adulterated."

Previously, in a report published in The BMJ, experts claimed that breast milk purchased online can pose serious health risks to infants, largely due to a lack of regulation. Human milk is not tested for contamination or disease and could be stored incorrectly.

A brain abnormality may be responsible for more than 40 percent of deaths from sudden infant death syndrome (SIDS), a new study suggests.

The abnormality is in the hippocampus, a part of the brain that influences breathing, heart rate and body temperature. This abnormality may disrupt the brain's control of breathing and heart rate during sleep or during brief waking that happens during the night, the researchers report.

"This abnormality could put infants at risk for SIDS," said lead researcher Dr. Hannah Kinney, a professor of pathology at Harvard Medical School in Boston.

Kinney can't say for sure that this abnormality is a cause of SIDS. "We don't know at this stage. This is the first observation of this abnormality," she said. "It's just an observation at this point."

Before this brain abnormality can be called a cause of SIDS, Kinney said, they have to find out what causes this abnormality and determine if it alone can cause SIDS.

For the study, Kinney's team examined sections of the hippocampus from 153 infants who died suddenly and unexpectedly between 1991 and 2012. The deaths were classified as unexplained -- which includes SIDS -- or from a known cause, such as infection, accident, murder or lack of oxygen.

Kinney's group found that 41.2 percent of infants who died for an unexplained reason compared with 7.7 percent of those whose death was explainable had an abnormality in the part of the hippocampus known as the dentate gyrus.

Among the 86 infants whose death was classified as SIDS, 43 percent had this abnormality, the researchers added.

This change in the dentate gyrus suggests there was a problem in development at some point late in the life of the fetus or in the months after birth, Kinney said.

Kinney added that this abnormality has only been seen under the microscope after death, so a child cannot be tested for the abnormality.

"There are no signs or symptoms that predict SIDS or warn families that this problem is there or that SIDS is going to occur," she said.

The report was published online Nov. 24 in the journal Acta Neuropathologica.

"Until we understand more about this abnormality, parents should follow the safe sleep recommendations of the American Academy of Pediatrics," Kinney said.

The recommendation is to place an infant alone in a crib on the back without toys or pillows as bolsters. "The same messages we have always had are still applicable," she said.

SIDS is the leading cause of death of infants younger than 1 year of age in the United States, the researchers said.

Dr. Sayed Naqvi, a pediatric neurologist at Miami Children's Hospital, noted that this brain abnormality has been found in epilepsy, but this is the first time it has been linked to SIDS.

"This needs to be confirmed and more research done to say this is a cause of SIDS," he said.

Marian Willinger, a special assistant for SIDS at U.S. National Institute of Health's Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in a statement, "The new finding adds to a growing body of evidence that brain abnormalities may underlie many cases of SIDS."

"The hope is that research efforts in this area eventually will provide the means to identify vulnerable infants so that we'll be able to reduce their risk for SIDS," she added.

For all the impressive advancements in medical technology, researchers and scientists still face a daunting challenge when they study the habits of the adorable but uncommunicative subjects called human infants.

In order to study infants without overwhelming them, scientists often try to mask the massive machines needed to view brain activity either by having the child sleep through it or by covering it in kid-friendly decorations. Other researchers have devised decidedly low-tech ways of reading an infant’s interest in a subject, even when they can’t say a single word.

In a study released Monday in the Proceedings of National Academy of Sciences, doctors used a special machine to examine infant brain activity as they start to learn language skills.

Patricia Kuhl, a professor of speech and hearing sciences at University of Washington and the lead author of the study, said the research indicated the area of the infants’ brain that controlled motor skills lit up when they heard certain words. The activity indicated that the infants are trying to mimic adults and speak much earlier before they say their first word.

However, Kuhl said, the study was important because of both the surprising findings and the way researchers were able to get them. To “read” the infant’s brain activity, they used the cutting-edge device called a magnetoencephalograph, that was quiet and nimble enough to read the chaotic world of infants’ brain activity.

Kuhl said unlike an MRI machine, which is extremely loud and requires a patient to be totally still, the magnetoencephalograph is nearly silent. However the infants still had to be strapped into a chair, so to keep them entertained the researchers were tasked with making silly faces and holding up toys all in the name of science.

“You want them to like the lab,” said Kuhl. “It’s decorated with fish and it’s got little stickies [on it.] It’s ... very baby friendly. We wave toys and we’re very aware and of their curiosity and of their desire to play. We do everything to make them comfortable.”

In a 2013 study published in Psychological Science, researchers used MRI machines to examine baby’s brain activity in response to different stimuli. However, to get the infants into a machine where they could not move, the researchers had the babies go in after they fell asleep naturally. They also used ear coverings so the loud MRI machine didn’t wake the infants.

MRI machines can be so distressing for patients because of claustrophobia or other fears about being in the hospital that a New York Hospital installed a pirate-themed scanner to put children (and some parents) more at ease.

“The genius is in this machine. ... There’s no noise and the baby can listen and can move,” said Kuhl of the magnetoencephalograph. “The ability for the first time to do this kind of recording in this kind of technical advanced machine ... [it’s like] we’re putting [on] a stethoscope.”

Fei Xue, a professor of psychology at the University of California Berkeley, has done numerous studies examining how infants learn and react to new toys or information. She said researchers have plenty of tricks to keep babies focused on the tasks at hand.

Xue said most studies only last between 5-10 minutes because the infants will get bored if they're longer. If they want a baby to focus on an object, they darken the room and light up the object to draw the baby's attention.

“In a way, it’s easy to work with infants,” said Xue. “They’re very curious and they’re interested in the world.”

To measure if babies are interested in an object or scene without getting verbal confirmation, Xue and her fellow researchers simply follow the infant’s eye movement. While there are special computer programs, Xue said often it just comes down to a researcher holding a stopwatch and watching the infant through a monitor.

In spite of the infants’ inability to speak, Xue said, understanding their thought process can reveal how they learn, which could eventually help shape education programs.

“When they go to preschool and elementary school ... they will help us to know how to structure the school system,” said Xue of her young subjects. “Understanding these really young humans is important.”